Why are tomatoes red? Research by Dutch scientists discovered that a stressful event millions of years ago, like a meteorite crash, triggered the change in the plant's genome:
"Such a big genome expansion points to extremely stressful conditions,' says René Klein Lankhorst, the Wageningen UR coordinator of the tomato genome research project. 'We suspect that the meteorite crash and the resulting solar eclipse had created conditions difficult for plants to survive. A distant ancestor of the tomato plant then reacted by expanding its genome considerably in order to increase its chances of survival."
When conditions subsequently improved again, this ancestor of the tomato got rid of a lot of genetic ballast, but the genetic base for fruit formation had already been developed by then, the tomato fruit acquired its red colour and certain genes which produced toxins disappeared, says Klein Lankhorst. In this way, the tomato differentiates itself from a family member, the potato, which has no edible fruits.